Water in high pressure steam header

larryh

150 psi fire tube boiler. Feed water is on a recirculating loop and is fed to boiler via a fisher control valve. The eeprom in the valve control failed open and the Boiler began to fill with water. This condition was caught by a sharp stationary engineer and safely shut down. QUESTION: what happens if the water continues and fills into the steam header?

Jamie Hall

That depends... what does the boiler feed? if it's a turbine or an engine, the water -- even a small amount of it -- will destroy it in remarkably short order. Otherwise... nothing much. Other than shutting everything down. if there are pressure reducing valves, they could also be damaged.

EBEBRATT-Ed

@larryh
Steam is always condensing in the steam header so water always has to have a way to get out. If it didn't you would have constant hammering. It either goes back into the boiler or out through a steam trap.

You should consider putting overflow steam traps pipe at a level near the top of your gage glass. Then if you have a feed water valve failure the water will go back to the boiler feed tank

SlamDunk

Nothing much. But my system may be different. I have four boilers on a common header at 100psi. Sometimes, I get mild hammering but mostly, i find it with no or low pressure on the gage. High water cut off prevents boiler from firing. Another boiler picks up the load. I suppose, water drains to surge tank from traps on header.

mikeg2015

Depends on the system. On a large industrial system, on startup, you have to warm it slowly and open a bunch of drains to remove condensate that hte troops can’t all handle, otherwise the hammering with blow out piping. I’ve seen flanges on 12” 150psi elbows rip open.

Yes, on a turbine, they can ONLY be fed superheated steam. They work only on pressure/temperature reduction, not phase change.

Mike_Sheppard

I’ve seen this happen on several occasions. All were high pressure steam firetubes with no high level cut out. It can cause some pretty nasty water hammer.